O my Jesus, forgive us our sins, save us from the fires of hell, and lead all souls to Heaven, especially those in most need of Thy mercy.
This prayer was revealed to three children in Fatima in 1917. The prayer was given to the kids by Our Lady of Fatima. She asked the kids to recite this prayer after each decade of the Rosary. In 1930 the Catholic Church approved the prayer for public use and to be used while reciting all Rosaries.